Lack of depth problem

What are you driving them with? There are a lot of amps that allow no sound stage depth(few SS amps will). My Cary monoblocks will, and that depth increases dramically with the right driver tubes. There are more variables than just the speakers. Lots of things get in the way of ambience recovery(amp/pre/source/tubes/cables). Your room dimensions sound really nice for audio. Is there anything between the speakers? How far apart are they? Did you have much depth with the system before changing the speakers? This CD contains some tracks that are excellent diagnostic tools for setting up your system: (http://www.chesky.com/core/details.cfm?productcode=JD037&category=1)

I'm not a proponent of the parallel to the wall camp.

Generally speaking, and that is not carved in stone, I find most speakers sound best when they are toed in so the inside surface is barely visible from the listening position.

Different dispersion patterns and listening preferences will, of course, be the final determinants.

Agree with Newbee. Check out the Cardas site. Use simple (one/few performers, acoustic instruments, NOT multitracked heavily mixed rock), analog recordings (NOT digital) for optimizing. A good starting point for your speakers should be between 5'-9" and 7'-8" from the wall behind the speakers. Try to have as much room between the speakers as possible leaving a few feet on either sides (your room is narrow). Using a string make sure the distance from both speaker to your listening position is equal. Do not toe-in the speakers initially. Simply start at one distance from the back wall and move them 1" at a time until you have optimised the location. Once there, use smaller increments. Use minimal toe-in until the image "snaps" into focus. Always try one position and compare the sound with the previous position. Listen to the "accuracy" of the bass, naturalness of vocals, and other instruments.

This is a long, tedius process and can take several months to get right. Enjoy.

On what basis are you making the judgment that your setup lacks image depth? What are you listening to that you know images deeper, but isn't happening on your current system?

I should have mentioned in my previous post that there are two tests that will aid you specifically in the placement of your speakers(on the Chesky disc). The LEDR, explained here: (http://www.stereophile.com/features/772/index.html) and the "Acoustic Soundstage (Depth) Test".